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ABSTRACT Rubber lining is used as corrosion protection material in scrubbers, tanks, pipe systems etc of European flue gas desulphurization plants. Although these rubber linings show in cases more than 15 years life, re-rubber lining is still necessary. Due to the expected higher availability of the power station units the time scale of such replacement must be kept to a minimum. As an efficient method for removal of the old lining the high pressure water systems has proven successful. Based on one such case of re-lining the working steps and time scale are demonstrated. INTRODUCTION By reason of the sulphur contained in hard coal, lignite and heavy oil, sulphur dioxide is produced during the combustion process of these fuels in electric power plants. It is common practice today to install a plant for the purpose of reducing the extent of sulphur emissions in conjunction with the cleaning process of the flue gases emitted by these power plants. In Germany, such flue gas desulphurization plants (FGD) have been installed in power plants for over 15years. The flue gas desulphurization plants erected in Germany for this purpose were almost exclusively the type that operate according to the wet-scrubbing method. As a general rule, this process entails the washing of flue gases in large scrubbing towers (absorbers, scrubbers) by means of alkaline solutions and suspensions (limestone suspensions). In this process, the sulphur dioxide contained in the flue gases reacts with the alkaline components of the scrubbing liquid and/or scrubbing suspension. The gypsum producing processes, which utilize either limestone or calcium hydroxide suspensions, are one of most important and commonly used methods. In Germany, approximately 90°Aof all flue gas scrubbers installed in coal-fired power plants operate according to this process. Since the constructional materials utilized in the plant are subjected to a high degree of corrosive attack, corrosion protection measures are an absolute necessity. For this reason, the vast majority of flue gas scrubbers in German power plants were fitted with rubber linings to provide protection for the constructional materials made of stee1234.However, these rubber linings are also exposed to a wide range of chemical, thermal and abrasive loads which, as a matter of course, will limit their service life as a result of progressive aging and deterioration. Despite this normal aging sequence, a service life exceeding 120,000 operating hours has been achieved in several instances in the case of rubber linings applied in coal-fired power plants. The oldest flue gas desulphurization plants installed in German coal-fired power plants have now been in operation for well over 17 years and those installed in power plants fired with lignite for slightly more than 10years. Consequently the rubber linings applied in several of these flue gas scrubbers are in need of being replaced. The process of rubber lining replacement will be illustrated in the following segments using the example of a flue gas scrubber in a lignite fired power plant, which has been re-lined.
- Europe > Germany (0.65)
- North America > United States (0.46)
- Energy > Power Industry (1.00)
- Energy > Oil & Gas > Upstream (1.00)
ABSTRACT Extended requirements regarding their degree of efficiency, profitability and availability are settled to the Flue Gas Desulphurization Plants, which are presently under construction or in the engineering stage. Therefore the corrosion protection system established today like FRP linings, resin coatings, and/or rubber linings must offer a long service life and a good price/quality performance. In the paper the approved corrosion protection materials will be presented, with special regard to Seawater FGD Plants. The actual market requirements will be discussed in details as well as the new related European standards. The state of the art will be demonstrated based on current references INTRODUCTION Sulfur dioxide SO2 is one of a number of gaseous pollutants fuel generated by fossil combustion. It can be effectively controlled by air pollution control processes. Flue gas desulphurization (FGD) involves this removal of sulfur dioxide contained in the gases produced by the combustion of fossil fuels. The retrofitting of coal-fired power stations with FGD plants was initiated in the United States of America and Japan almost 40 years ago, with most of Europe following suit in the late 1970?s. Countries in other parts of the world followed. The experience acquired over this extensive period of time has brought about an optimization of flue gas desulphurization processes, a noticeable simplification of the scrubber design, as well as an improvement of the corrosion protection materials used in the flue gas desulphurization plant parts. PROCESSES EMPLOYED FOR THE DESULFURIZATION OF FLUE GASES A large and varied number of methods have been designed for and employed in the desulphurization of flue gases. The most noteworthy processes currently being employed are the wet desulphurization procedures and among those, primarily the gypsum producing methods utilizing either limestone or calcium hydroxide suspensions are worth mentioning. The sulfur dioxide in the gases reacts for example with the limestone slurry, which has normally a pH of 5.5 to 6.0, forming calcium sulfite: (chemical equation available in full paper) Through oxidation of the calcium sulfite with oxygen, gypsum is formed in the scrubber sump: (chemical equation available in full paper) These particular processes were almost exclusively utilized in the construction of the flue gas desulphurization plants designed for the electric power plants in Europe. In the meantime, the seawater desulphurization process used at power plants that are located close to seashores has also achieved some importance. Over 70 of these units have meanwhile been installed in different parts of the world. In this process the sulfur dioxide in the gases reacts with the seawater, which has a pH of 5.5 to 7.0, forming hydrogen sulfite ion: (chemical equation available in full paper) Through oxidation of the hydrogen sulfite ion with oxygen, sulfate ions are formed either in the scrubber sump or in a separate tank: The effluent from the plant is discharged directly back to the sea. SURFACE PROTECTION AND CONSTRUCTION MATERIALS The structural materials of a flue gas desulphurization plant are subjected to a wide spectrum of chemical, thermal and mechanical stress conditions.
- North America > United States (1.00)
- Europe (0.70)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.45)
- Geology > Mineral > Sulfate > Gypsum (0.45)
- North America > United States (0.89)
- Asia > Japan (0.89)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
ABSTRACT This paper describes an approach used to select corrosion resistant materials for a wet flue gas desulphurization FGD) plant. Material selection and correct application supervision are paramount when designing linings as corrosion control method. The use of various corrosion resistant linings in the major components of the FGD plant were reviewed and some examples of generic lining applications are shown to illustrate the importance to line carbon steel equipments, generally the most cost effective corrosion control measure for this process system. INTRODUCTION The Steag Company of Germany decided in the 1990's to build a hard coal fired power plant in the Gulf of Iskenderun, Turkey. A consortium of Siemens and Gama Tekfen were the contract leader and responsible for the construction of the whole plant (2 units with 1210 MW). An important part of the power plant contract supply is the gas treatment system - the Flue Gas Desulphurisation Plant for reducing the SO2content. A typical flow chart for a limestone/gypsum FGD Plant is shown in Figure1. The FGD plant at Iskenderun consists of: ? 2 Absorbers with raw gas and clean gas ducts ? 2 Stacks ? 8 Tanks and 1 Clarifier This paper describes in detail the corrosion protection systems selected and indicates why such system is used in each area of the plant. For a client buying a wet FGD system, linings are a critical and integral part of the plant for which long lasting guarantees are essential. A lining system which fails is extremely costly for both the client and the lining supplier. Lining systems serving as environmental protection and as a corrosion protection method should therefore combine permanent adhesion to the substrate to which they are applied, excellent chemical and abrasion resistance, good thermal stability, low permeability and adequate flexibility. Additional requirements of such lining systems are; ? Long lifetime ? Ease of repair ? Low investment costs MATERIAL SELECTION Because an FGD plant encompasses a broad range of operational conditions, no only one generic type of corrosion protection system is suitable for all sections of the FGD system. To correctly select the optimum lining system the service conditions must be very well known. For example the absorber has the following operational conditions: A tolerance for temperature variations and excursions, deposit build up, and an ability to withstand vibration and local Ioadings, must also be taken into account when selec- ting lining systems. In view of these demanding requirements, rubber linings based on bromobutyl rubber (BIIR) were selected as the corrosion protection system in the FGD scrubbers and ancillary tankage. Bromobutyl rubber offers; ? Excellent abrasion resistance ? Low permeability ? High diffusion resistance 4). The butyl or bromobutyl types (BIIR) were applied at a thickness of 4 mm, having been manufactured on a roller head plant. For this application, two versions of the same rubber lining were installed: ? Prevulcanised rubber linings from type BIIR ? Selvulcanizing rubber linings from type BIIR The selfvulcanizing material will be applied in an unvulcanised condition, the curing taking place under ambient temperatures. The curing time can be also reduced if desired, by increasing the temperature with steam, either hot air or at room temperature. Precured rubber sheets are cured in the manufacturer's autoclave and are applied with special glue. No post treatment is necessary. Spray applied flake filled linings based on vinyl ester resins have been applied as the corrosion protection
- Materials > Metals & Mining (1.00)
- Energy > Power Industry (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Commercial Services & Supplies > Security & Alarm Services (1.00)
ABSTRACT Over a period of approximately 35 years the manufacturers of the rubber lining and resin coating industries have executed the lining of several million square meters of steel surfaces in hundreds of scrubbers of flue gas desulfurization (FGD) plants world-wide, thereby effectively protecting them against corrosion. The application of special rubber lining and resin coating materials as surface protection in flue gas desulfurization plants has been proven effective. Coating and rubber lining materials which are applied in many FGD plants world-wide and are successfully in use for a long time, must meanwhile been replaced after long operating periods to ensure the continued function of the plants. The paper describes the re-lining with resin coating and rubber lining of a scrubber in a FGD plant after approximately 18 years. INTRODUCTION By reason of the sulfur contained in hard coal, lignite and heavy oil, sulfur dioxide is produced during the combustion process of these fuels in electric power plants. It is common practice to install a plant for the purpose of reducing the extent of sulfur emissions in conjunction with the cleaning process of the flue gases emitted by these power plants. The first flue gas desulfurization plants (FGD) have been installed in power plants in the USA and in Japan approximately 35 ago years and over 25 years ago in Europe. The flue gas desulfurization plants erected for this purpose were almost exclusively the type that operate according to the wet-scrubbing method. As a general rule, this process entails the washing of flue gases in large scrubbing towers (absorbers, scrubbers) by means of alkaline solutions and suspensions. In this process, the sulfur dioxide contained in the flue gases reacts with the alkaline components of the scrubbing liquid and/or scrubbing suspension. The gypsum producing processes, which utilize either limestone or calcium hydroxide suspensions, are one of most important and commonly used methods. Approximately 90% of all flue gas scrubbers installed in coal-fired power plants operate according to this process. CONSTRUCTION MATERIALS AND SURFACE PROTECTION The structural materials of a flue gas desulfurization plant are subjected to a wide spectrum of chemical, thermal and mechanical stress conditions. Such conditions may range from dry, hot flue gas loads with the possible formation of acid condensates, and in particular highly concentrated sulfuric acid, over wet loads with abrasive suspensions at temperatures of 45 ° to 70 ° C, to water vapor saturated gases under oxidizing conditions with the simultaneous formation of acid condensates. Each of these stress conditions requires construction and lining materials that are corrosion resistant. As a result of the higher chloride content in the flue gases - and consequently also in the scrubber suspension - and giving due consideration to the prevailing temperatures and pH- values, the selection of usable special steel alloys is extremely limited, which therefore- particularly in the case of corrosion resistant structural materials - frequently allows only the application of expensive nickel-based alloys. However, when selecting carbon steel (and/or concrete) as structural material, the following types of protective lining materials are available: · Rubber linings, in particular soft rubber linings · Synthetic resin coatings (in particular those containing flaky, plate-like fillers - "flakes") Rubber lining. As a result of their elasticity, soft rubber linings are largely insensitive to mechanical loads, which may be caused by movements of the structural material. They exhibit excellent chemical resistance properties when utilize
- North America > United States (0.89)
- Europe (0.67)
- Europe > Russia > Northwestern Federal District > Komi Republic > Timan-Pechora Basin > Pechora-Kolva Basin > Usa Field (0.89)
- Asia > Japan (0.89)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- (2 more...)
ABSTRACT Rubber linings are applied as a corrosion protection system for the interior surfaces of C- steel in flue gas desulphurization plants (FGD). Given that over twenty years of operational experience has now been accumulated in the utilization of this material in corrosion protection systems, staff members of the power station operators, of the rubber lining industry as well as independent test institutions in Germany have jointly worked out an instruction sheet in which 1. Test procedures determine the usability of soft rubber linings in flue gas desulphurization plants as well as 2. Testing criteria and standard values for the assessment of the service life of soft rubber linings in flue gas desulphurization plants have been formulated. The objective of this lecture is to introduce and explain the contents of this new instruction sheet. INTRODUCTION In the course of the past 20 plus years, specialized companies of the German rubber lining industry have applied over 1.5 million square meters of steel surfaces with rubber linings in European flue gas desulphurization plants (FGD), in order to protect the steel surfaces from attack by corrosive media. The lining of the scrubbers and process tanks is carried out entirely on site by means of soft rubber sheets whereas the rubber lining of pipes is executed in the workshop. The rubber linings applied in flue gas desulphurization plants represent a considerable value for the operators of power plants. Consequently, two factors are of paramount importance to these operators: one being the selection of the optimal rubber lining material and the other, to be furnished with specific information pertaining to the anticipated end of the service life of the applied FGD rubber lining. This data enables the operators to reach an informed decision as to the necessity of re-lining based on the condition of the lining and to schedule the rehabilitation as far in advance as possible. Associates of the VGB - Technische Vereinigung der Grosskraftwerksbetreiber e.V. (Technical Association of Superpower Station Operators), of the Fachverband der Gummierungsindustrie (Technical Association of the Rubber Lining Industry) as well as independent test institutions have now jointly worked out an instruction sheet which provides information relative to test procedures to determine the usability and effectiveness of rubber lining materials based on long-term operational experience in conjunction with laboratory tests. This leaflet also contains testing criteria and benchmark values for the assessment of the remaining service life of soft rubber linings in flue gas desulphurization plants. FLUE GAS DESULPHURIZATION METHODS An extensive and very diverse range of processes have been developed and also implemented for the desulphurization of flue gases. The most noteworthy ones are the so-called wet scrubbing methods and of those, in particular the gypsum-producing methods, utilizing limestone or calcium hydroxide suspensions. Over 90 % of all existing flue gas scrubbers in European coal-fired power plants are operated on the basis of these methods. AGGRESSIVE ENVIRONMENTS ENCOUNTERED IN GYPSUM-PRODUCING WET DESULPHURIZATION UNITS In gypsum-producing wet desulphurization units, the different plant parts are exposed to considerable chemical, thermal and mechanical attack. Therefore a corrosion protection of the structural material - which so far has almost exclusively been steel - is required. Two areas in particular are lined with rubber sheets in order to protect them from corrosion: Figure 1: Typical flow sheet ofa FGD plant Scrubber Area The flue gases entering the scrubber are cleaned accordi
- North America > United States (0.28)
- Europe > Germany (0.25)
- Energy > Power Industry (1.00)
- Energy > Oil & Gas > Upstream (1.00)